Diagnosis and radiation: what every man should know

Dr Shivona Moodley, a radiation oncologist, explains the diagnostic process as well as the role of radiation in prostate cancer.

You can listen to this article below, or by using your favourite podcast player at pod.link/oncologybuddies

Prostate cancer is a malignant disease that starts in the prostate gland. Many patients are asymptomatic at the time of diagnosis and screening to detected early-stage disease, especially in high-risk populations, which often leads to curative treatments with good long-term quality of life.

How is prostate cancer diagnosed?

PSA testing

Prostate-specific antigen (PSA) is a protein that is produced by the prostate and tested by drawing a blood sample. PSA is the most commonly used and most valuable test for early detection of prostate cancer. 

The likelihood of prostate cancer increases with elevated PSA values. However, a higher level doesn’t necessarily mean there is cancer present as there are a variety of other causes for a mild to moderately elevated PSA.

Imaging

Various imaging modalities are used in the diagnosis and staging of prostate cancer; your team of specialists will help decide which imaging would suit your needs. 

A multi-parametric MRI can be helpful in determining the local extent of disease in the prostate gland, lymph nodes, and pelvic bones. 

A CT scan can be used to assess the lungs, liver, bones, and other organs for spread of disease. 

A PSMA/PET is a special kind of PET scan that locates a protein called prostate-specific membrane antigen (PSMA) on the surface of prostate cancer cells.

A PSMA/PET scan is a full body scan and has added value in assisting with radiation therapy planning in more advanced or metastatic disease. 

Prostate biopsy 

A prostate biopsy is a procedure where a sample of tissue is removed from the prostate by using a needle. The urologist may use a trans-rectal ultrasound or an MRI to guide the biopsy and enhance diagnostic accuracy. The specimen is then sent off to the lab where a pathologist will examine it in detail under the microscope to assess for cancer cells.

When it comes to treatments for prostate cancer, there are many good options. One effective treatment option is radiation therapy, either alone or in combination with other therapies like hormonal therapy or surgery. 

The different kinds of radiation therapy for prostate cancer

Brachytherapy 

Brachytherapy is also known as internal radiation. This form of radiation travels very short distances and allows sparing of normal surrounding tissue from radiation.

Low-dose rate (LDR) brachytherapy is when multiple radioactive seeds (the size of a grain of rice) are placed through the perineum into the prostate gland. These seeds stay in the prostate and emit a low dose of radiation over a few months. Over time, the seeds become dormant but will remain in your body.

High-dose rate (HDR) brachytherapy is the temporary placement of radioactivity within the prostate gland using thin needles and catheters. The radioactive source temporarily moves through the catheters, emits a dose of radiation within the prostate gland and moves out again. 

Brachytherapy can be used alone in very low-risk to intermediate-risk-favourable disease, or in combination with external beam and hormonal therapy with higher risk disease. It can also be used in the salvage setting in patients with a recurrence, following prior treatment with external beam radiation.

External Beam Radiation Therapy (EBRT)

Radiation therapy uses high-energy X-rays that are produced by a machine called a linear accelerator. This beam of energy enters the body through the skin surface and is targeted at the prostate, seminal vesicles, and lymph nodes in order to kill cancer cells.

It can be used as the main treatment instead of surgery; after surgery if the PSA begins to rise; or in the metastatic setting for palliation.

It’s a highly conformal, well-tolerated and effective form of treatment when used alone or in combination with hormone therapy, brachytherapy or both. 

Stereotactic Body Radiation Therapy (SBRT)

This is a radiation therapy technique that allows radiotherapy to be delivered to a limited area over a few treatment sessions. 

With SBRT, advanced treatment delivery technologies and radiation planning parameters are used to deliver higher doses per day in a safe and effective manner.

It’s often used to treat sites of metastatic spread including the lung, lymph nodes, and bones, but can also be used to treat disease in the prostate gland.

The landscape around diagnosis and treatment of prostate cancer is a daunting one. It requires a multi-disciplinary team and a holistic patient-centred approach to help formulate a treatment plan that is individualised to each patients needs and specific disease characteristics. 

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